Lassig Bridge & Iron Works was originally founded by Moritz Lassig. Mr. Lassig was originally born in the Kingdom of Saxony in 1831. After studying at the Chemnitz University of Technology, he immigrated to the United States in 1851.
That fall, he accepted a position with Stone & Boomer, designing Howe Trusses. At this firm, it is believed that Lassig worked on portions of railroad and canals in Illinois. As a trusted assistant of L.B. Boomer, he continued to work at the firm until the American Civil War. During and after the Civil War, Lassig and Boomer worked together on the replacement several bridges that had been destroyed during war.
After the war, Lassig was hired as the General Superintendent at American Bridge Company of Chicago, where he spent approximately one year*. He left in 1871 when he opened his own shops at Clark and 16th Street in Chicago. These shops were soon purchased by the Chicago & Western Indiana Railroad to expand right-of-way.
*note: while some sources suggest Lassig spent only one year with American Bridge Company (of Chicago), his obituary suggests he stayed with the firm until 1876.
After this solo venture, Lassig partnered with John Alden, formerly of Leighton Bridge Works. The two reorganized Leighton into the Rochester Bridge Works, operating it for five years.
In 1882, Lassig began a solo venture at Clybourn and Wrightwood Avenues in Chicago. By 1886, Alden and Lassig agreed to go their separate ways, and Lassig focused his life on his own firm.
In the 1890s, Lassig Bridge & Iron Works was producing a considerable amount of steel, almost exclusively for railroad use. During the mid to late 1890s, most railroad bridges on the Chicago & North Western, the Milwaukee Road, the Omaha Road and the Rock Island were using Lassig products.
Lassig sold his work to the newly formed American Bridge Company in 1900, and ceased his involvement in bridge building. He died in Germany in January of 1902.
In the end, Lassig was perhaps the most prolific railroad bridge fabricator for the Midwestern United States. It has been widely reported that Lassig was always eager to evolve his bridge designs.
During the early Alden & Lassig years, lattice truss production continued based on Leighton designs. In addition, the Double Intersection Warren Pony Truss was perfected for railroad use, requiring less steel than a traditional Howe Truss. Many of these were replaced by the 1890s, but were rebuilt by Lassig for use as wagon overpasses.
One of the most iconic designs is the Lassig Quadrangular Riveted Through Truss. Built for the Chicago & North Western Railway; the Chicago, Minneapolis, St. Paul & Omaha Railway; the Chicago, Rock Island & Pacific Railroad and the Union Pacific Railroad, these trusses made up a significant portion of all trusses built by Lassig.
In addition to the Quadrangular Truss, standard pin connected trusses were built for the Chicago, Burlington & Quincy Railroad as well as the Chicago, Milwaukee & St. Paul Railway.
American Bridge Company phased out the Lassig name by 1902, but production at the Chicago plant remained until 1928. The buildings remained until the late 1980s, when they were demolished for redevelopment. The land is now occupied by several commercial buildings.
Today, Lassig bridges can still be seen throughout the Midwest. Many of the early grade separations in Chicago, as well as mainlines for ex C&NW lines in particular remain nearly exclusively Lassig products.
The author has added counts of bridges built for each railroad, based on Bridgehunter.com reports from March 2021. It is worth noting there is almost certainly uncounted spans for every railroad, and some spans may be double counted due to relocations of various spans. The goal of this count is to demonstrate how widely used Lassig products were, and how certain railroads purchased Lassig products exclusively.
A sample of plaques and projects completed by Lassig Bridge & Iron Works can be seen below. Unlike many builders, Lassig had little change in the plaque design or format during their 18 year run.
Early plaques featured a shield shaped design with decorative features and said "M. Lassig, Builder". Plaques after 1889 appear to use a standard rectangle shape with rounded indented edges, with text saying "Built by the Lassig Bridge and Iron Works Chicago Ill".
The plaque shape remained for at least two years after American Bridge took over, although these plaques stated "Built by American Bridge Company, Lassig Branch".
By analyzing the mounting hole size and shapes on the plaques, one can learn a great deal about the age of said bridge. It appears that the pre-1889 plaques had two small bolts, located in the upper corners. The 1889-1896 plaques had two larger bolts, located midway on the sides. The post-1896 plaques seem to have had a single bolt, located upper center on the plaque. 1896 seems to be the only year of overlap of these styles.